1. Field of the Invention PA1 a substrate, which has a first major surface and a second major surface that are positioned opposite each other; PA1 an electron-emitting device, which comprises a first electrode, to which a first voltage is applied, and a second electrode, to which a voltage Vf is applied, that are mounted, with an interval, on the first major surface; PA1 an anode electrode, which is located opposite and at a distance H from the first major surface; PA1 first voltage application means, for applying to the second electrode the voltage Vf that is higher than the first voltage; and PA1 second voltage application means, for applying to the anode electrode a voltage Va that is higher than the voltage Vf, PA1 wherein a space defined between the anode electrode and the electron-emitting device is maintained in a reduced-pressure condition, and PA1 wherein, when a value Xs=H*Vf/(.pi.*Va) is established for a plane that is substantially perpendicular to the first major surface, a width w of the second electrode, in a direction substantially parallel to the first major surface, equals or exceeds 0.5 times the value Xs and is smaller than or equals 15 times the value Xs. PA1 a substrate having a first major surface and a second major surface that are positioned opposite each other; PA1 an electron-emitting device, which includes a first electrode, to which a first voltage is applied, and a second electrode, to which a voltage Vf is applied, that are mounted, with an interval, on the first major surface; PA1 a second substrate, on which an anode electrode, which is located opposite and at a distance H from the first major surface, and an image-forming member are mounted; PA1 first voltage application means, for applying to the second electrode the voltage Vf that is higher than the first voltage; and PA1 second voltage application means, for applying to the anode electrode a voltage Va that is higher than the voltage Vf, PA1 wherein a space defined between the anode electrode and the electron-emitting device is maintained in a reduced-pressure condition, and PA1 wherein, when a value Xs=H*Vf/(.pi.*Va) is established for a plane that is substantially perpendicular to the first major surface, a width w of the second electrode in a direction substantially parallel to the first major surface equals or exceeds 0.5 times the value Xs and is smaller than or equals 15 times the value Xs. PA1 a substrate, which has a first major surface and a second major surface that are positioned opposite each other; PA1 an electron-emitting device, which comprises a first electrode, to which a first voltage is applied, and a second electrode, to which a voltage Vf is applied, that are mounted, with an interval, on the first major surface; PA1 an anode electrode that is located opposite and at a distance H from the first major surface; PA1 first voltage application means, for applying to the second electrode the voltage Vf that is higher than the first voltage; and PA1 second voltage application means, for applying to the anode electrode a voltage Va that is higher than the voltage Vf, PA1 wherein, when viewed from the anode electrode, the second electrode is sandwiched between the first electrode pair, and PA1 wherein, when a value Xs=H*Vf/(.pi.*Va) is established for a plane that is substantially perpendicular to the first major surface, a width w of the second electrode sandwiched between the first electrode pair equals or exceeds 0.5 times the value Xs and equals or is smaller than 15 times the value Xs. PA1 a substrate having a first major surface and a second major surface that are positioned opposite each other; PA1 an electron-emitting device, which comprises a first electrode, to which a first voltage is applied, and a second electrode, to which a voltage Vf is applied, that are mounted, with an intervening interval, on the first major surface; PA1 a second substrate, on which an anode electrode, which is located opposite and at a distance H from the first major surface, and an image-forming member are mounted; PA1 first voltage application means, for applying to the second electrode the voltage Vf that is higher than the first voltage; and PA1 second voltage application means, for applying to the anode electrode a voltage Va that is higher than the voltage Vf, PA1 wherein, when viewed from the anode electrode, the second electrode is sandwiched between the first electrode pair, and PA1 wherein, when a value Xs=H*Vf/(.pi.*Va) is established for a plane that is substantially perpendicular to the first major surface, a width w of the second electrode sandwiched between the first electrode pair equals or exceeds 0.5 times the value Xs and equals or is smaller than 15 times the value Xs.
The present invention relates to an electron-emitting device having an innovative arrangement, and to an image-forming apparatus, such as an electron source apparatus or an image-displaying apparatus, that uses such an electron-emitting device.
2. Related Background Art
Conventionally, roughly there are two types of well known electron-emitting devices: one is a thermionic cathode, and the other is a cold-cathode. A field emission type (hereinafter referred to as an "FE"), a metal/insulator-metal type (hereinafter referred to as an MIM), and a surface conduction electron-emitting type are classified into the cold cathode.
A well known FE example is disclosed in "Field Emission", W. P. Dyke and W. W. Dolan, Advances in Electron Physics, 8.89 (1956), or in "Physical Properties of Thin-film Field Emission Cathodes With Molybdenum Cones", C. A. Spindt, J. Applied Physics, 47, 5248 (1976).
Additional, current discussions are: "Fluctuation-free Electron Emission From Non-formed Metal-insulator-metal (MIM) Cathodes Fabricated By Low Current Anodic Oxidation", Toshiaki Kusunoki, Jpn., J. Applied Physics, vol. 32 (1993), pp. L1695; and "An MIM-Cathode Array For Cathode Luminescent Displays", Mutsumi Suzuki, et al., IDW '96, (1996), pp. 529.
An example surface conduction type is disclosed in a report by M. I. Elinson in Radio Engineering Electron Physics, 10 (1965). The surface conduction electron-emitting device employs a phenomenon whereby an electron emission occurs when a current is supplied in parallel to the surface of a thin film that is formed on a small area of a substrate. The surface conduction electron-emitting devices are devices that use an SnO.sub.2 thin film (described in the Elinson report), a device that employs an Au thin film (reported by G. Dittmer, Thin Solid Films, 9, 317 (1972), and a device that employs an In.sub.2 O.sub.3 /SnO.sub.2 thin film (reported by M. Hartwell and C. G. Fonstad, IEEE Trans. ED Conf., 519 (1983)).
A plane type electron-emitting device shown in FIGS. 50A and 50B and a step type electron-emitting device shown in FIG. 52 are other surface conduction type devices proposed by the present inventor.
In FIGS. 50A and 50B, schematic diagrams illustrate a conventional surface conduction electron-emitting device. In FIG. 50A, a specific top plan view of an electron-emitting device is shown, and in FIG. 50B, a specific transverse cross-sectional view of the device is shown. In the views shown, a high-potential side electrode 1002 and a low-potential side electrode 1003, which together constitute the electron-emitting device, are mounted on a substrate 1001 and are connected to a power source (not shown). The high-potential side electrode 1002 is connected to an electroconductive thin film 1004, while the low-potential side electrode 1003 is connected to an electroconductive thin film 1005. The thicknesses of the electrodes 1002 and 1003 are several tens of nm to several .mu.m, and the thicknesses of the films 1004 and 1005 are 1 to several tens of [nm]. A gap 1006 is defined that substantially electrically discontinues the thin films 1004 and 1005.
For these conventional surface condition electron-emitting devices, generally, before electron emission, an electron-emitting region is formed by performing a so-called "energization-forming" process for electroconductive thin film. That is, in the "energization forming" process, a direct-current voltage, or a very gradual boosting voltage, i.e., a voltage of 1 V, is applied at both ends of an electroconductive thin film to locally destroy, deform or degenerate the electroconductive thin film, so as to form an electron-emitting region wherein the electrical resistance is high.
Furthermore, when a process is performed called activation, during which, for energization, an organic gas is introduced into a vacuum, a carbon film is deposited at the distal ends of the electroconductive thin films facing each other across the gap between them, so as to form an electron-emitting region having an improved electron emission characteristic. When a voltage is applied to the electroconductive thin films and a current is supplied to the surface conduction electron-emitting device that is provided by the energization forming operation and the activation operation, electrons are emitted from the electron-emitting region.
Recently, a flat type display apparatus has become popular for which a liquid crystal, instead of a CRT, is used as an image-forming apparatus, such as a display device. However, since this display apparatus is not an emissive type, it must include a backlight, and as result, a demand exists for an emissive display apparatus. An emissive type display apparatus is, for example, an image forming apparatus that comprises: an electron source, wherein multiple surface conduction electron-emitting devices are arranged; and a phosphor, which emits visible light using electrons output by the electron source (e.g., U.S. Pat. No. 5,066,883). An example electron source wherein multiple surface conduction electron-emitting devices are arranged is one having multiple surface conduction electron-emitting devices that are arranged in parallel as multiple arrays (ladder-shaped arrays), and wherein both ends (both device electrodes) of each electron-emitting device are connected by wiring (common wiring) (e.g., Japanese Patent Application Laid-Open Nos. 64-31332, 1-283749 and 1-257552).